Preharvest factors affecting postharvest quality of horticultural products

Fruit and vegetables are important in modern diets providing essential nutrients, nutraceuticals and enjoyment on consumption. Product quality dictates repeat purchases only after satisfying consumer tastes. Overall quality, including appearance, taste, texture and freedom from defects, is influenced by key preharvest factors affecting plants during growth and development. All plants must be suited to their growing environments of temperature, rainfall, wind, soils and slope. A balanced nutrient programme is essential to optimise growth and minimize mineral deficiencies or excesses that can lead to physiological disorders both in the field and postharvest. Calcium deficiency creates a wide range of physiological disorders including fruit splitting, internal flesh browning, blossom end rot, cavity spots, black heart, chilling injury, malformation and tipburn in green leafy vegetables and susceptibility to diseases. Some fruit disorders appear only during storage postharvest. Little detailed information is available about calcium requirements of subtropical and tropical fruit. Incidence of pests and diseases present major challenges in many tropical and subtropical production systems; integrated production systems, based on accurate identification of pests and pathogens together with close monitoring/assessment of populations, is required to target persistent offenders. Use of cover nets, with or without incorporated pesticides, are an important new technology and economical addition to farmers' defence armories. While organic farming system yields can be compromised, at least initially, returns can be higher than traditional production systems as products meet increasingly discerning environmentally friendly consumers who pay more for “safe” food. Some successful cooperative models exist locally as examples of the technologies and knowledge available. Plant breeding will increase productivity, nutritive value and overall quality both at and after harvest. Genetic engineering can produce plants with desirable attributes, but society is not yet convinced that benefits gained outweigh risks. The new gene editing technique (CHRISPR) has great potential to create new, desirable, safe and economically successful cultivars adapted to a range of environmental, edaphic and social production systems faster than traditional breeding. Farmers, scientists, extension specialists and market personnel must work together to provide knowledge, best practices and enabling tools for growers to ensure preharvest conditions are optimised for production of high quality horticultural crops that satisfy and reward discerning consumers.